MCi Crusader II 1989 Maintenance Manual page 135

Date 1-1-89
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MC-9 MAINTENANCE MANUAL
DISASSEMBLY
WARNING: Pull rod bolt is under spring
tension. To avoid possible injury, exercise
care when removing pull rod bolt to slowly
relieve spring tension.
1. Place the spring "cell" in a vise with pull rod bolt end up
and the hex end of the rod held securely in the vise jaws. Slowly
and cauti0t1sly remove the pull rod bolt This will release the
spring load as the bolt is removed.
2. Remove the springs. Remove the pull rod bolt from the
piston.
3. Remove the seal grommet from the pull rod bolt Remove
cover from the pull rod.
4. Take pull rod out of vise.
NOTE: The spiral pin, button, and mount-
ing nut are removed at the time the valve is
removed from the vehicle dash. Insert a
punch or rod in the plunger pin hole to keep
the plunger from turning when_ removing
the nut at the bottom of the valve.
5. Remove the plunger and spring. Remove plunger 0-ring.
6. Remove the two cover screws and separate the cover
from the body. Remove the cover seal 0-ring and the inlet and
exhaust valve.
7. Remove the piston. then the lower large piston 0-ring,
and then the upper piston 0-ring.
REPAIR
1. Wash all metal parts in cleaning solvent and dry. Wipe
reusable rubber parts clean.
2. Inspect al~ parts for excessive wear or deterioration.
3. Inspect the plunger and piston bores of the control valve
for nicks and burrs. Check spring for cracks, distortion, or
corrosion.
4. Inspect the inlet and exhaust valve and grommets for wear
or deterioration.
5. Replace all parts not considered serviceable during these
inspections, especially rubber parts.
REASSEMBLY
Prior to assembly, lubricate all 0-ringsand bearing surfaces
of the body and cover with recommended lubricant. MCI/TMC
Part No. 21-7512-11.
1. Install 0-ring on plunger. Place spring on plunger.
2. Insert plunger. with spring and grommet installed, in body.
3. Install inlet and exhaust valve over protruding end of the
plunger. The double beaded side of the inlet and exhaust valve
should be up against the body seat
4. Position cover to body seal in body. Attach the cover to the
body with two screws.
5. Install the piston 0-ring (large diameter 0-ring in bottom
piston groove). Install the piston with 0-ring.
6. Depress the plunger, and with a punch or rod hold it from
turning while installing the plunger stem nut. Torque on the
stem nut.should be between 30-40 inch pounds (3.3-4.5 Nm).
7. The control button should be installed and held in place
by the spiral pin after the valve is mounted on the vehicle floor
and held by the mounting nut.
INVERSION VALVE
When the control valve is operated, the inversion valve
operates permitting air in the isolated reservoir to apply the
brakes. The inversion valve also operates automatically when
air pressure drops to a predetermined pressure.
With no system air pressure, the inversion valve inlet valve is
open and its exhaust is closed. See figure 4-5. On initial
build-up, as air enters the isolated reservoir to which the inver-
sion valve supply port is connected. it will pass by the open inlet
and out the delivery ports. When the system pressure reaches
50-60 psi (345-414 kPa) and the control valve is operated, air
will pass into the inversion valve from the control valve. This air
flows in one control port and exerts a force on the inversion
valve piston. At a pressure between 60-70 psi (414-484 kPa),
the piston moves agai_nst the resistance of the two piston
springs. The piston exhaust seat moves away from the inlet and
exhaust valve, opening the exhaust passage. The inlet valve
spring and supply air at the inlet valve
will
cause it to seat Air
will then exhaust from the exhaust port. .
The inversion valve is mounted on a bracket which is
attached to the drive axle at the radius rod mounting bracket
Figure 4•5. TR-2 Inversion Valve Installed